1. Field of the Invention
The present invention relates to a composition for use in an adsorption treatment capable of easily and efficiently adsorbing and removing components to be adsorbed such as odor components, for example, carbonyl groups-containing compounds such as aldehydes and ketones, and odorless and harmful gaseous components; a method for producing the same; and products formed with the same such as filters for air-cleaning. The technique of the present invention is especially effective in adsorbing and removing the above-described components from rooms of cars, houses and buildings.
2. Description of the Prior Art
At large equipment such as sewage treatment plants and thermal disposal plants in urban areas, odor components are removed from gases by use of sprinkler system cleaning device which uses washing water prepared by dissolving medicine reactive with odor components into water. At small and closed spaces such as toilets, rooms of houses and buildings, and rooms of cars, it is impossible to install a large-scale sprinkle system cleaning device. In these spaces, therefore, odor components are usually removed by use of physical adsorbents such as an activated charcoal.
It is confirmed that, in a car, there are gases generated when fuels and oils decompose, combustion products from cigarettes, malodorous or odorless and harmful gaseous components such as organic compounds evaporating from adhesives used for adhesion of interior boards and interior parts, and heat insulating foamed resins. In rooms of houses and buildings, there are combustion products from cigarettes, and harmful gaseous components evaporated from heat insulating materials, plywood, and adhesives. These harmful gaseous components recently constitute a problem of sick house.
These malodorous or odorless and harmful gaseous components (hereinafter, these are simply referred to as gaseous components in some cases) contain carbonyl group-containing compounds such as formaldehyde, acetaldehyde, acrolein, and benzaldehyde. As described above, air-cleaners for use in toilets, rooms of houses and buildings, and in cars usually contain physical adsorbents such as an activated charcoal; however, an activated charcoal is not capable of sufficiently adsorbing the carbonyl group-containing compounds.
The physical adsorbents such as an activated charcoal have other problems. The physical adsorbents have adsorption sites, and when they adsorb and remove the components to be adsorbed from the gas, they capture the components into the adsorption sites. At this time, the physical adsorbents also adsorb moisture (i.e. water) in the gas together with the components. If the adsorption sites are saturated with the moisture, the components cannot be sufficiently adsorbed. On top of this, the physical adsorbents release the components which it once adsorbed when it is subjected to high temperature.
In order to develop an adsorbent capable of sufficiently adsorbing gaseous components when it is used in a room of house where moisture is present and in a car where its room temperature may become high by sunlight, various studies have been conducted. The present inventors have found that a phenol compound is reactive with the above-describe carbonyl-group containing compounds in the presence of moisture. They have made an invention directed to a composition containing the phenol compounds and a water adsorbing substance for carrying the phenol compounds, and have already filed an application for the invention (Japanese patent application No. 10-271386)
The composition disclosed in Japanese patent application No. 10-271386 is in the form of fine particles. When the composition is used in an adsorption treatment device or a filter for air-cleaning, it is interposed between permeable members. A material with tight surface is not preferable for interposing the composition in order to keep high permeability and high treatment efficiency, and therefore, a material having a large number of pores with a certain diameter is used for the permeable member. For example, a non-woven cloth with a low density is used as the permeable material. In this case, if the composition has a small particle diameter, the composition falls through the pores of the non-woven cloth. The adsorbent with such a problem does not have a commercial value or does not sufficiently adsorb components to be adsorbed.
In order to avoid the above problem, the composition is preferably in the form of grains larger than fine particles. In addition, the composition in the form of grains is easy to handle, and contributes to keep the working environment clean. In such a situation, there is a demand for finding out the conditions for preparing the adsorption treatment composition in the form of grains with a certain size.
The present invention has been achieved in view of the foregoing. An objective of the present invention is to provide a composition for use in adsorption treatment which is easy to handle; a method for easily preparing the composition in the form of grains without inhibiting its adsorption ability; products such as an adsorption treatment device and a filter for air-cleaning formed with the composition; and a method of adsorption treatment.
According to the present invention, the composition for use in adsorption treatment includes an adsorbing substance reactive with components to be adsorbed in the presence of moisture, a water-absorbing substance, and a binder. The weight of the binder is 1.3 to 8 percent with respect to the weight of the water-absorbing substance. Through the use of these substances blended at this weight ratio, the resultant composition is formed into grains having high strength without losing its adsorption ability.